Method of obtaining leaf tobacco with low content of nicotine

ABSTRACT

AN AQUEOUS SOLUTION OR AQUEOUS SUSPENSION OF A FILM FORMING AGENT IS SPRAY-SPREAD ON THE SURFACES OF TOBACCO LEAVES AFTER THE STOPPING OF FIELD-GROWN TOBCCO, TO FORM AN INSOLUBLE THIN FILM THEREON. AS A FILM-FORMING AGENT THERE MAY BE USED HIGHER ALCOHOLS HAVING 16 TO 22 CARBON ATOMS IN THE MOLECULE AND THEIR DERIVAITIVES; ANIMAL, VEGETABLE AND MINERAL WAXES; HIGH POLYMERS OR SUBSTANCES WHICH ARE GENERALLY AS A VEHICLE.

United States US. C]. 47-58 1 Claim ABSTRACT OF THE DISCLOSURE Anaqueous solution or aqueous suspension of a filmforming agent isspray-spread on the surfaces of tobacco leaves after the stopping offield-grown tobacco, to form an insoluble thin film thereon. As afilm-forming agent there may be used higher alcohols having 16 to 22carbon atoms in the molecule and their derivatives; animal, vegetableand mineral waxes; high polymers or substances which are generally as avehicle.

This application is a continuation of Ser. No. 654,082, filed July 18,1967 and now abandoned.

BACKGROUND OF THE INVENTION 1) Field of the invention The presentinvention relates to a method of obtaining leaf tobacco with low contentof nicotine. More particular, this invention relates to a method for thetreatment of leaf tobacco wherein the surface of the leaf is coated witha film-forming material after the ripe stage of field tobacco.

(2) Description of the prior art As hitherto known methods for loweringthe nicotine content of leaf tobacco, there may be mentioned, forinstance, the cultivation of low nicotine varieties, the reduction inthe amount of nitrogen fertilizer used, the dense cultivation oftobacco, and others. However, these known methods have in practicedisadvantages because they effect undesirably on the yield and qualityof leaf tobacco.

BRIEF SUMMARY OF THE INVENTION The present invention is intended toobviate such disadvantages in conventional known methods.

An object of this invention is to provide an improved method foreconomically obtaining leaf tobacco having low nicotine content and goodquality.

According to the present invention the nicotine content in the leaftobacco can be decreased and moreover, its quality can be improved byspray-spreading an aqueous solution or aqueous suspension offilm-forming agent on the surfaces of tobacco leaves after the toppingof fieldgrown tobacco to form a thin film thereon, thereafter primingsaid leaves at the proper mature stage in a usual known method and thendrying the leaves thus obtained.

DETAILED DESCRIPTION INCLUDING PREFERRED EMBODIMENTS The film-formingagent used in the present invention is an agent which has such effectthat it may form an insoluble thin film on the surface of body when itis spread thereon in the form of aqueous solution or aqueous suspension.

As a film-forming agent, there may be used, for instance, an aqueoussolution or aqueous suspension of 3,6ii,b35 Patented Oct. I2, 1971higher alcohols having 16 to 22. carbon atoms in the molecule, such ascetyl alcohol, stearyl alcohol, eicosyl alcohol and docosyl alcohol andtheir derivatives; waxes, such as carnauba wax, cotton seed wax,beeswax, wool wax, paraffin wax, montan wax, microcrystalline wax; andhigh polymers, such as polyvinyl acetate, polyvinyl alcohol and thelike. In addition, substances which are generally used as vehicle may beemployed, for instance, polyoxyethylene dodecyl ether, allkylphenolpolyethylene glycol ether, polyoxyethylene alkylary ether and ligninsufonate, for example, sodium lignosulfonate.

The mechanism in the reduction of nicotine content resulted from thespreading of the above described filmforming agent may be believed asfollows:

As well known, the stomata of tobacco leaves lose the ability of openingafter the mature stage of leaves and consequently, the O -pressure inthe intercellular spaces of leaves tends to decrease to the state inwhich the anaerobic respiration proceeds. When the whole surfaces oftobacco leaves are spread with a film-forming agent in that period,films thus produced cover the surfaces stomata of the leaves so that thelack of oxygen is brought on nd hence the anaerobic respiration ispromoted actively. When the anaerobic respiration is conducted, thebonding of nicotine to organic acid is cut and a part of bound nicotineis liberated. Due to the strong volatility, the liberated nicotine isscattered from the surfaces of green or drying leaves into the air, andthus, the nicotine content in the leaf tobacco may be decreased.

In the present invention, the above described film-forming agent ispreferably spread on the leaf tobacco by use of-sprayer and the like inthe form of aqueous solution or aqueous suspension having in general aconcentration not more than 3%. In that case, it should be careful thatsaid agent is spread on the outer and rear or back surfaces of the leafin such a manner that an insoluble film can be formed completely withoutunevenness.

The stage at which said filmforming agent is spread on the leaf tobaccois preferred to be after the topping of field-grown tobacco. Further,with regard to the frequence of spreading said film-forming agent,although the more the frequence is, the greater eifects on the nicotinecontent and the price per kg. are provided, spreading more than threetimes is not advantageous economically from the point of labour.

The same result may be obtained in the present invention by dipping theprimed tobacco leaves in a solution of film-forming agent and dryingthem before flue-curing. In this case, the concentration of dippingsolution is preferred to be not more than 5% and desirably somewhathigher, as compared with that in the spreading. The dipped tobaccoleaves may be flue-cured by a conventional method after drying of theagent.

For the tobacco leaves thus treated, the improvement in the quality,such as the lower nicotine content and higher price per kg. is observedremarkably.

Thus, the improved method according to the present invention givesreally a great contribution to the tobacco industry.

In the following, this invention is further described with reference toexamples which are illustrative but not limitative thereof.

EXAMPLE 1 (1) Preparation of agent 15 parts of carnauba wax and 5 partsof microcrystalline wax were mixed and the mixture was molten withheating. A solution containing 1 part of sodium oleate, 5 parts ofmorpholine and 2 parts of tricresyl phosphate dissolved in parts ofwater was then added to said molten mixture gradually with heating andstirring to emulsify. The resulting emulsion was diluted to twelve timesof its original volume with water to prepare a spreading agent.

(2) Spreading process The field grown tobacco, the variety Hicks, wastopped at the flowering stage and the above-mentioned agent was spreadevenly on the outer and rear or back surfaces of leaves at a rate of 180ml. per plant by means of sprayer. In the A-section, the agent wasspread once immediately after topping (A-section) and in the B-section,it was spread two times immediately and 9 days after the topping(-B-section).

(3) Investigation of quality (price per kg.) and nicotine content Yieldof Nicotine content dried leaves (by wt. per 10 a., Irlce per percent)kg. kg. (index) Section A 1. 87 288.0 108 B 1. 56 256. 7 117 Control 2.55 287. 100

EXAMPLE 2 (1) Preparation of agent 3 parts of sodium oleate were addedto 5 parts of monooxyethylene stearyl alcohol and 5 parts ofmonooxyethylene docosanol and the resulting mixture was heated to meltand dissolved in 100 parts of warm water to produce an emulsion, whichwas then diluted further to twelve times of its original volume withwater to form a spreading agent.

(2) Spreading process The investigation was carried out as in Example 1and the result is shown in the following table.

Nicotine Yield of content dried leaves (by wt. per a., Price perpercent) kg. kg. (index) Section C 1. 57 242. 2 99 D 1. 24 266. 5 119Control 1. 26 226. 3 100 EXAMPLE 3 1) Preparation of agent A commercialvehicle containing 10% of polyoxyethylene alkylarylether and 20% ofsodium lignosulfonate was diluted with water of 750 times of its volumeto produce a spreading agent of 0.04% content.

(2) Spreading process The field-grown Bright Yellow was tested and theaforesaid agent was spread days after the topping once at a rate of 330ml. per plant in the same manner as in Example 1 (E-section).

4 (3) Investigation of quality (price per kg.) and nicotine content Theinvestigation was carried out according to Example 1 and the result isshown in the following table.

Nicotine Yield of content dried leaves (by wt. per 10 a., Price perpercent) kg. kg. (index) Section E 2. 07 193. 0 109 Control 2. 46 196. 0

EXAMPLE 4 (1) Preparation of agent (2) Spreading process The above agentwas spread 10 days after the topping of Bright Yellow once at a rate ofml. per plant in the same manner as in Example 1 (F-section).

(3) Investigation of quality (price per kg.) and nicotine content Theinvestigation was carried out according to Example 1 and the result isshown in the following table.

Nicotine Yield of content dried leaves (by wt. per 10 a., Price perpercent) kg. kg. (index) Section F 1. 97 232.0 111 Control 2. 44 234. 5100 What is claimed is:

1. In a method of obtaining field-grown leaf tobacco wherein thefield-grown tobacco is topped and the leaves subsequently primed anddried, the improvement which comprises reducing the amount of nicotinein the dried leaves by spraying the plants in the field after topping atleast once with an aqueous composition consisting essentially of notmore than about 3% by weight of at least one film forming agent to forma thin film of said agent over substantially the entire leaf surface,said film serving as a gas impervious barrier to inhibit aerobicrespiration, said agent being selected from the group consisting ofcarnauba wax, cotton seed wax, beeswax, wool wax, paraffin wax, montanwax, microcrystalline wax, cetyl alcohol, stearyl alcohol, eicosylalcohol, docosyl alcohol, monooxyethylene derivatives of said alcohols,polyvinyl alcohol, and polyvinyl acetate.

References Cited UNITED STATES PATENTS 2,128,973 9/19318 Tisdale et a147-5-8 UX 2,203,274 6/ 1940 Anderson et a1 476 2,720,451 10/ 1955Anderson et al. 47-58 UX 3,016,295 1/1 962 Davidson et al. 71-78 X3,157,964 11/1 964 Ferguson et al. 4-7-1 3,205,059 9/1965 Roberts 71-1223,220,823 ll/ 1965 Mihara et al. 4758 3,399,990 9/ 1968 Humphrey et al47-58 X 3,410,676 11/1968 Hill 71--77 ROBERT E. BAGWILL, PrimaryExaminer US. Cl. X.R. 131-140 B

